For example, Japanese Unexamined Patent Application Publication No. 2005-64186 (US2005/0034466) describes a cooling system including a heat absorbing member for performing heat exchange between a cooling object and brine, a heat radiating member for performing heat exchange between the brine which has received heat from the heat absorbing member and air, and a brine circuit through which the brine flows, and a pump for pressurizing the brine. The brine is circulated through the heat absorbing member and the heat radiating member by the pump. That is, discharge pressure of the pump is exerted to the heat absorbing member and the heat radiating member.
Japanese Unexamined Patent Application Publication No. 2002-353668 describes a cooling apparatus having a heat conductive plate, a fin as a heat radiating member disposed on one surface of the heat conductive plate and a passage-forming member as a heat absorbing member closely disposed on the opposite surface of the heat conductive plate. The passage-forming member has a depressed portion for forming a cooling medium passage (brine passage) and bridge portions extending from a bottom surface of the depressed portion toward the heat conductive plate. The bridge portions have the height same as the depth of the depressed portion such that the bridge portions contact the heat conductive plate. The bridge portions are surrounded by the cooling medium passage.
An electronic device as a cooling object is fixed to a surface of the passage-forming member on a side opposite to the heat conductive plate through a heat spreading plate. Heat generated by the electronic device is transferred to the fin through the bridge portions of the passage-forming member and the heat conductive plate, and is radiated from the fin.
In the above cooling apparatuses, the brine circuit is a closed circuit, and the brine is circulated by means of the pump. The discharge pressure of the pump is exerted to the heat absorbing member and the heat radiating member. That is, an internal pressure of the brine circuit is higher than an atmospheric pressure. Therefore, if a brine passage in the heat absorbing member or the heat radiating member is broken, the brine will leak from the brine passage, resulting in defects of the electronic devices, such as short-circuit.